1. Field of the Invention
The present invention concerns a wind power installation comprising a pylon, a pod mounted rotatably on the pylon, a generator arranged within the pod and having a rotor and a stator, and at least one fan in the region of the pod.
2. Description of the Related Art
Such wind power installations have long been known in the state of the art. There is a large number of design configurations which operate in part with oil cooling, in part with air cooling or also with water cooling. In that respect, all situations involve the problem that losses occur, which also occur in the form of heat and which have to be dissipated. As each component has given thermal stress limits which must be observed, it is therefore necessary to provide adequate cooling in order to be able to dissipate the excess heat and avoid damage due to excessively raised temperatures.
The invention is directed in particular to wind power installations which operate with air cooling. Cooling systems of that kind are known from the wind power installations from Enercon (Types E-40, E-44, E-58 or also E-66). In that case a fan is let into the pod, which draws in cooling air from the exterior and blows it into the interior of the pod so that the cooling air flows through an opening in the generator and in so doing cools the individual components which heat up. The heated air then either generally flows back into a closed cooling circuit or issues outwardly through the air gap between the spinner and the stationary part of the pod.
With the rise in output power of the generators, the cooling requirements of those generators also increases in order to be able to reliably keep the temperatures thereof below critical limits, even in the full load operating condition.
The wind power installations in accordance with the state of the art involve a so-called windward rotor. In other words the pod of the wind power installation is oriented in such a way that the rotor blades are disposed at the side of the pod, which is towards the wind. A fan is arranged on the side remote from the wind (the lee side) in the pod wall. That fan sucks in air from the exterior and conveys it into the pod. There the air flows around the components in the pod and thus provides for heat dissipation and thus a cooling effect.
It will be noted however that in operation of the fan dust, moisture and rain which are also present in the air are also sucked in and transported into the interior of the pod. That results in unwanted fouling of the pod, with the consequence of a faster rate of wear of components (just because of the abrasive effect of dust or sand) and a high level of air humidity in the pod, which is unwanted precisely when the weather is rainy, with all its adverse accompanying phenomena.